My Pittsburgh weather guru Kevin Benson used the F-word last night... FROST!
Come to think of it, that time of year is already upon us. Kevin's map showed frost potential in the NW counties of Pennsylvania for our last night in September, which makes sense, since October 10th is our average first frost slightly further south in SW Pennsylvania counties. Kevin said weather conditions would be just right for frost last night: clear skies, calm winds and a low dew point in the 30's.
So how can you extend the season of your annual flowers and tender tomatoes?
A light cover works best and something as economical as newspaper will work while plastic covers are less desirable. An old bed sheet is good, but old towels are usually too heavy unless supported over top of fragile plants.
We usually have a half dozen lightweight mesh leaf tarps for bundling landscape debris, so the ones without holes in them are usually my first choice as frost protection. They are large enough and light enough to work well.
Of course another solution is temporarily moving tender potted plants inside or under cover (picnic table or patio umbrella) because no one really wants the growing season to end just yet.